In the field of regenerative medicine, it has been a challenge to establish a method to proliferate cells of interest at a higher rate. In the fields of cell engineering and fermentation engineering, in order to increase the yield of the cells of interest themselves or to increase the efficiency of the cells (or tissue) of interest to produce products, it is desired to proliferate more efficiently the subject cultured cells (or cells constituting cultured tissue).
Conventionally, for the above purposes, various cell growth factors have been used. One example among the most frequently used growth factors is basic fibroblast growth factor (hereinafter, it may be referred to as “bFGF”). bFGF is known as a substance to exhibit an effect of promoting proliferation of various mesodermal and neuroectodermal cells in addition to fibroblasts and is a growth factor that is frequently used in promoting proliferation of various kinds of subject cells.
However, as the currently available bFGF is very expensive, it is financially difficult to use the growth factor in a relatively large quantity for cell proliferation. Moreover, using bFGF for the purpose of cell proliferation may become a significant cause to increase the cost of cell manufacturing and tissue regeneration involving the said proliferation.
Under these circumstances, research and development of a low-cost, mass-producible substance that has cell growth-promoting capability to replace the expensive cell growth factors such as bFGF are underway so far. For example, Patent Documents 1 to 3 listed below respectively describe a peptide that possesses cell growth-promoting capability and the respective Patent Literatures describe that by using the peptide, the growth rate of the test cells was increased.